SEATTLE — The last time the U.S. men’s national soccer team played Belgium, in a March 2026 match billed as a World Cup tuneup, it got “a good reality check.”Those were head coach Mauricio Pochettino’s words after a 5-2 Belgian drubbing. The game spiraled out of control in the second half. Wave after wave of talented Belgium attackers turned a balanced contest into a bloodbath.It felt, at the time, like evidence that the U.S. still couldn’t measure up to Europe’s best.But now, as the teams prepare for a World Cup round-of-16 clash, it feels mostly irrelevant.“Last time it was a friendly game, so it’s not the same,” U.S. wingback Sergiño Dest said of the March exhibition. “Then, you can try things out.”It feels irrelevant for a variety of reasons, but largely because the U.S. did “try things out.” Pochettino tried a tactical system that he had not used in several months and has not used since.Namely, he played not one but two attack-minded fullbacks, and only two stay-at-home defenders. Belgium exploited the space left gaping when one of those fullbacks, Tim Weah, a natural right winger, pushed high up the field.Ever since, the U.S. has played with a third stay-at-home (or mostly-at-home) defender, Alex Freeman, who has given the team a blend of stability and dynamism that’s been crucial to their World Cup success.It was also part of their turnaround last fall. After a 2-0 loss to South Korea in September, Pochettino switched to a formation with three true center backs. In October, the shape then morphed into a hybrid, but the key, from Sept. 9 to present, has been that the right-sided defender — whether a center back like Miles Robinson or a fullback like Freeman — did not bomb up and down the wing.Except once.That Belgium match was the lone exception.Pochettino asked Weah to attack as a right winger, and sometimes even to press Belgium’s left fullback …… while also defending the best player on the field, Belgian left winger Jérémy Doku.Doku, for many reasons including this one, terrorized the USMNT on that Saturday afternoon. Belgium’s first three goals, plus a fourth that was disallowed for a handball, all started at his feet on the left wing.